I am trying to make my own exception classes this ...

# getting-started

[electrolobzik]

I am trying to make my own exception classes this way:

// 4xx without errorCode
class UnknownClientRequestException(
    message: String,
    error: ClientRequestException
): RuntimeException(
    message = "$message (server code: ${error.response.status.value}, message: ${error.response.status.description})",
    cause = error
)

But I am getting compile time errors: Cannot find a parameter with this name: message , Cannot find a parameter with this name: cause
What am I doing wrong?

[Adam S]

RuntimeException is a Java class, and you can't use named arguments with Java classes

https://discuss.kotlinlang.org/t/what-is-the-reason-for-not-allowing-named-arguments-for-java-interop/4571

[electrolobzik]

If RuntimeException is declared in stdlib as an expect class , how will be translated on other platforms? I see that Ktor also uses it as a base class for it’s own exceptions. If it is multiplatform class it is weird that I can’t use it in normal kotlin way.

[Adam S]

on JVM it's an actual typealias, and in other targets it's an actual class (e.g. on JS)

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-runtime-exception/

[electrolobzik]

When I use it in the common multiplatform module why I can’t use the named arguments if it is the native Kotlin expect class?